Airplane with a fuel cell device

ABSTRACT

An aircraft comprises a fuel cell device which can be operated with hydrogen from a hydrogen tank and with oxygen drawn from the surrounding air, and further comprises a superconducting magnetic energy storage unit (SMES unit) which is disposed, together with the hydrogen tank, in a cryogenic container, wherein the cryogenic container does not have an active cooling system or a liquid hydrogen generating device, and has a volume for holding a maximum of 40 kg liquid hydrogen.

The invention relates to an aircraft comprising a fuel cell device which can be operated with hydrogen from a hydrogen tank and with oxygen drawn from the surrounding air, and further comprising a superconducting magnetic energy storage unit (SMES unit) which is disposed, together with the hydrogen tank, in a cryogenic container.

An energy generating device comprising a fuel cell device which can be operated with hydrogen from a hydrogen tank and with oxygen drawn from the surrounding air, and further comprising a superconducting magnetic energy storage unit (SMES unit) which is disposed, together with the hydrogen tank, in a cryogenic container is known from DE 10 2007 042 711 B4. In this case, synergistic effects are achieved by storing the liquid hydrogen required for operating the fuel cell device in the same tank as the SMES unit, since only one cooling unit is required. This energy generating device comprises a hydrogen condenser, which is housed in the tank and which produces the liquid hydrogen while at the same time cooling the SMES unit. Thus in order to produce the liquid hydrogen, energy is spent or is diverted from the energy that is generated. This assembly can therefore be used only for stationary plant operation.

DE 196 00 936 discloses an energy generating device for a seaplane, which uses liquid hydrogen and superconductors and which comprises a liquid hydrogen tank and a separate SMES unit, with the SMES unit being cooled by the liquid hydrogen from the liquid hydrogen tank. The hydrogen that is evaporated by an inflow of heat is reliquefied by means of a heat exchanger.

DE 10 2011 014 565 A1 discloses an aircraft comprising a fuel cell device which can be operated with hydrogen from a hydrogen tank that is disposed in a cryogenic container. The oxygen is drawn from the surrounding air. The fuel cell device is used to supply the aircraft with electric power for a limited amount of time. In this case, the tank is designed to hold 50 to 60 kg of hydrogen.

DE 10 2011 013 577 A1 discloses a system for storing hydrogen and electric energy.

Proceeding from the above, it is the object of the invention to provide an energy generating device that is structurally simple and compact but will meet the necessary safety requirements, and that can supply electric energy in an aircraft in cases of transitional load, especially during on-ground stops.

This object is attained according to the invention by the features specified in claim 1. Advantageous embodiments are specified in the dependent claims.

The electric energy required to supply the output power for a transition load of a dynamic fuel cell system without interruption is stored in the SMES unit, which is cooled in the cryogenic environment of the hydrogen store of the fuel cell system. The particularly high energy density of an SMES unit and the dual use of the cryogenic environment decrease the weight of the system as a whole. Since the special constraints of air travel necessitate the lowest possible weight, the hydrogen tank is refilled after every flight. The tank is therefore configured as relatively small, with dimensions up to a maximum of 40 kg hydrogen. Refilling the tank before every flight allows an active cooling system to be dispensed with, thereby decreasing the overall structural expenditure and weight. It is further ensured that, in the event of a leak or a consumption of the entire hydrogen supply, the superconductor and the aircraft as a whole will not be damaged. The aircraft remains maintenance-free even with an uncooled superconductor.

In the following, the invention will be specified in greater detail in reference to the attached drawing.

FIG. 1 shows a schematic representation of an energy generating device 10 for an aircraft, which is not shown. The energy generating device comprises an ambient air inlet 12 for the intake and purification of ambient air (for example, removing sand, etc.) and for supplying the air to an electromechanical compressor 14, which feeds the compressed air to a fuel cell device 16, which comprises a membrane unit 18 and an energy generating unit 20.

A hydrogen tank 22 for holding liquid hydrogen supplies hydrogen to membrane unit 18, where the hydrogen reacts with the oxygen supplied by compressor 14, resulting in the generation of electric energy in energy generating unit 20 with the formation of water. The generated electric energy is supplied to an SMES unit 24, which uses part of the energy to power compressor 14 while the majority of the generated energy remains available for powering electric loads 26. Electric loads 26 are any electric devices in an aircraft, in particular the computer system and the lighting and air-conditioning systems.

Hydrogen tank 22 and SMES unit 24 are housed in a common cryogenic container 28, so that the coil (not shown) of SMES unit 24 is cooled by the cryogenic hydrogen. Cryogenic container 28 has only passive heat insulation means, and no active cooling devices. Also, no means for liquefying hydrogen is provided, which would increase energy consumption.

Thus although the duration of use or of energy supply of the device according to the invention is limited, the dimensions of the hydrogen supply can be configured for routine flight times and on-ground times during intermediate stops. As a result, preferably only a portion of the hydrogen is consumed during normal operation, while another portion, more particularly about 50%, remains available for cooling purposes.

LIST OF REFERENCE SIGNS

-   10 energy generating device -   12 ambient air inlet -   14 compressor -   16 fuel cell device -   18 membrane -   20 energy generating unit -   22 hydrogen tank -   24 SMES unit -   26 load -   28 cryogenic container 

1. An aircraft comprising a fuel cell device which is operable with hydrogen from a hydrogen tank and with oxygen drawn from the surrounding air, and further comprising a superconducting magnetic energy storage unit (SMES unit) which is disposed, together with the hydrogen tank, in a cryogenic container, wherein the cryogenic container does not have an active cooling system or a liquid hydrogen generating device, and has a volume for holding a maximum of 40 kg liquid hydrogen.
 2. The aircraft according to claim 1, wherein the cryogenic container has a volume for holding a maximum of 30 kg liquid hydrogen.
 3. The aircraft according to claim 1, wherein the aircraft comprises an electromechanical compressor unit for compressing ambient air for supply to the fuel cell device.
 4. The aircraft according to claim 1, wherein the electric output from the fuel cell device is fed to the SMES unit.
 5. The aircraft according to claim 3, wherein the compressor unit is electrically connected to the SMES unit for a supply of energy. 